Visser, E. J. W. | Search bioRxiv

bioRxiv2024

Flower bud cooling protects pollen development and improves fertility during heatwaves

Early pollen development is a bottleneck for plant fertility in heatwave conditions, thus affecting yield stability. Mechanisms that protect this process and explain variation in tolerance level between genotypes are poorly understood. Here we show that sepal transpiration in young, still closed, flower buds reduces the impact of heat on developing tomato pollen and that this mechanism is enhanced by the major tomato pollen thermotolerance QTL, qPV11. By direct measurement of the flower bud core temperature and transpiration we show this process, which we term flower bud cooling, depends on heat-induced opening of sepal stomata and that the transpiration enhancing effect of qPV11 requires functional stomatal regulation and is specific to the sepals. Large-scale evaluation of populations in both a production field and greenhouse showed that qPV11 improves pollen viability and fruit set in heatwave-affected complex cultivation environments. These findings highlight enhanced flower bud cooling as a naturally evolved protection mechanism against heatwaves and qPV11 as genetic component in the differential regulation of transpiration between reproductive and vegetative tissues and candidate variant for the breeding of climate-resilient tomato cultivars.

plant biology↗

bioRxiv2019

Ethylene-mediated nitric oxide depletion pre-adapts plants to hypoxia stress

Timely perception of adverse environmental changes is critical for survival. Dynamic changes in gases are important cues for plants to sense environmental perturbations, such as submergence. In Arabidopsis thaliana, changes in oxygen and nitric oxide (NO) control the stability of ERFVII transcription factors. ERFVII proteolysis is regulated by the N-degron pathway and mediates adaptation to flooding-induced hypoxia. However, how plants detect and transduce early submergence signals remains elusive. Here we show that plants can rapidly detect submergence through passive ethylene entrapment and use this signal to pre-adapt to impending hypoxia. Ethylene can enhance ERFVII stability prior to hypoxia by increasing the NO-scavenger PHYTOGLOBIN1. This ethylene-mediated NO depletion and consequent ERFVII accumulation pre-adapts plants to survive subsequent hypoxia. Our results reveal the biological link between three gaseous signals for the regulation of flooding survival and identifies novel regulatory targets for early stress perception that could be pivotal for developing flood-tolerant crops.

plant biology↗